DESCRIPTION: (Applicant's Description) We propose to develop a technique we call 3' cDNA SSH/SAGE for the identification of differentially expressed genes at the genomic level through modification and integration of key elements from differential display (DD), suppressive subtraction hybridization (SSH) and serial analysis of gene expression (SAGE) techniques. This technique focuses on the 3' sequence of all of the expressed genes in a given cell population, removes most of the abundant templates and some portion of homologous templates, and provides a sequence tag for each expressed gene to use in a database search. The differentially expressed genes between two populations will be identified by comparison of the resulting gene expression profiles. This technique should require limited initial materials, significantly decrease the difficulty of the gene identification process, directly use the EST database for gene identification, and thus provides a simple tool for the comparative analysis of gene expression at the genomic level.